Perili Köşk

Perili Köşk (originally known as the Yusuf Ziya Pasha Mansion) is a historical building at the Rumelihisarı neighbourhood of the Sarıyer district in Istanbul, Turkey. The building currently serves as the headquarters of Borusan Holding, as well as its art museum, called Borusan Contemporary.

Built in 1911, the castle-like red brick mansion with stained glass windows is located close to the Fatih Sultan Mehmet Bridge, on the European shore of the Bosphorus strait. The building has 9 floors above ground level and has a gross floor area of around 5,000 m2 (54,000 sq ft).

The popular nickname of the mansion, Perili Köşk (meaning the "Haunted Mansion" in Turkish) refers to its construction remaining partially unfinished for a long period (its second and third floors remained empty for decades.) The building's exterior appearance was carefully restored and completed in line with the original design between 1995 and 2000 by architect Hakan Kıran, who also renovated its interior.

Perili Köşk is also the title of a story by the Turkish author Ömer Seyfettin.